util/statetrace/arch/arm/tracechild.cc - public/gem5 - Git at Google

 /*
  * Copyright (c) 2010 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
  * not be construed as granting a license to any other intellectual
  * property including but not limited to intellectual property relating
  * to a hardware implementation of the functionality of the software
  * licensed hereunder.  You may use the software subject to the license
  * terms below provided that you ensure that this notice is replicated
  * unmodified and in its entirety in all distributions of the software,
  * modified or unmodified, in source code or in binary form.
  *
  * Copyright (c) 2006-2009 The Regents of The University of Michigan
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met: redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer;
  * redistributions in binary form must reproduce the above copyright
  * notice, this list of conditions and the following disclaimer in the
  * documentation and/or other materials provided with the distribution;
  * neither the name of the copyright holders nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include <stdint.h>

 #include <cerrno>
 #include <cstdio>
 #include <cstring>
 #include <iostream>

 #include "arch/arm/tracechild.hh"

 using namespace std;

 ARMTraceChild::ARMTraceChild()
 {
     foundMvn = false;

     memset(&regs, 0, sizeof(regs));
     memset(&oldregs, 0, sizeof(regs));
     memset(&fpregs, 0, sizeof(vfp_regs));
     memset(&oldfpregs, 0, sizeof(vfp_regs));

     for (int x = 0; x < numregs; x++) {
         regDiffSinceUpdate[x] = false;
     }

     assert(sizeof(regs.uregs)/sizeof(regs.uregs[0]) > CPSR);
 }

 bool
 ARMTraceChild::sendState(int socket)
 {
     uint32_t regVal = 0;
     uint64_t message[numregs + 1];
     int pos = 1;
     message[0] = 0;
     for (int x = 0; x < numregs; x++) {
         if (regDiffSinceUpdate[x]) {
             message[0] = message[0] | (1ULL << x);
             message[pos++] = getRegVal(x);
         }
     }

     size_t sent = 0;
     size_t toSend = pos * sizeof(message[0]);
     uint8_t *messagePtr = (uint8_t *)message;
     while (toSend != 0) {
         sent = write(socket, messagePtr, toSend);
         if (sent == -1) {
             cerr << "Write failed! " << strerror(errno) << endl;
             tracing = false;
             return false;
         }
         toSend -= sent;
         messagePtr += sent;
     }

     return true;
 }

 uint32_t
 ARMTraceChild::getRegs(user_regs &myregs, int num)
 {
     assert(num <= CPSR && num >= 0);
     return myregs.uregs[num];
 }

 uint64_t
 ARMTraceChild::getFpRegs(vfp_regs &my_fp_regs, int num)
 {
     assert(num >= F0 && num < numregs);
     if (num == FPSCR)
         return my_fp_regs.fpscr;

     num -= F0;
     return my_fp_regs.fpregs[num];
 }

 bool
 ARMTraceChild::update(int pid)
 {
     oldregs = regs;
     if (ptrace(PTRACE_GETREGS, pid, 0, &regs) != 0) {
         cerr << "update: " << strerror(errno) << endl;
         return false;
     }

     const uint32_t get_vfp_regs = 32;

     oldfpregs = fpregs;
     if (ptrace((__ptrace_request)get_vfp_regs, pid, 0, &fpregs) != 0) {
         cerr << "update: " << strerror(errno) << endl;
         return false;
     }

     for (unsigned int x = 0; x < numregs; x++)
         regDiffSinceUpdate[x] = (getRegVal(x) != getOldRegVal(x));

     return true;
 }

 int64_t
 ARMTraceChild::getRegVal(int num)
 {
     if (num <= CPSR)
         return getRegs(regs, num);
     else
         return (int64_t)getFpRegs(fpregs, num);
 }

 int64_t
 ARMTraceChild::getOldRegVal(int num)
 {
     if (num <= CPSR)
         return getRegs(oldregs, num);
     else
         return (int64_t)getFpRegs(oldfpregs, num);
 }

 ostream &
 ARMTraceChild::outputStartState(ostream & os)
 {
     uint32_t sp = getSP();
     uint32_t pc = getPC();
     uint32_t highestInfo = 0;
     char obuf[1024];
     sprintf(obuf, "Initial stack pointer = 0x%08x\n", sp);
     os << obuf;
     sprintf(obuf, "Initial program counter = 0x%08x\n", pc);
     os << obuf;

     //Output the argument count
     int32_t cargc = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
     sprintf(obuf, "0x%08x: Argc = 0x%08x\n", sp, cargc);
     os << obuf;
     sp += 4;

     //Output argv pointers
     int argCount = 0;
     int32_t cargv;
     do {
         cargv = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
         sprintf(obuf, "0x%08x: argv[%d] = 0x%08x\n",
                 sp, argCount++, cargv);
         if (cargv)
             if (highestInfo < cargv)
                 highestInfo = cargv;
         os << obuf;
         sp += 4;
     } while (cargv);

     //Output the envp pointers
     int envCount = 0;
     uint32_t cenvp;
     do {
         cenvp = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
         sprintf(obuf, "0x%08x: envp[%d] = 0x%08x\n",
                 sp, envCount++, cenvp);
         os << obuf;
         sp += 4;
     } while (cenvp);
     uint32_t auxType, auxVal;
     do {
         auxType = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
         sp += 4;
         auxVal = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
         sp += 4;
         sprintf(obuf, "0x%08x: Auxiliary vector = {0x%08x, 0x%08x}\n",
                 sp - 8, auxType, auxVal);
         os << obuf;
     } while (auxType != 0 || auxVal != 0);
     //Print out the argument strings, environment strings, and file name.
     string current;
     uint32_t buf;
     uint32_t currentStart = sp;
     bool clearedInitialPadding = false;
     do {
         buf = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
         char * cbuf = (char *)&buf;
         for (int x = 0; x < sizeof(uint32_t); x++) {
             if (cbuf[x])
                 current += cbuf[x];
             else {
                 sprintf(obuf, "0x%08x: \"%s\"\n",
                         currentStart, current.c_str());
                 os << obuf;
                 current = "";
                 currentStart = sp + x + 1;
             }
         }
         sp += 4;
         clearedInitialPadding = clearedInitialPadding || buf != 0;
     } while (!clearedInitialPadding || buf != 0 || sp <= highestInfo);
     return os;
 }

 bool
 ARMTraceChild::step()
 {
     const uint32_t bkpt_inst = 0xe7f001f0;

     uint32_t lr = getRegVal(14);
     uint32_t pc = getPC();
     uint32_t lrOp, subsOp;
     char obuf[128];
     bool patch = false;

     // Since ARM uses software breakpoints behind the scenes, they don't work
     // in read only areas like the page of routines provided by the kernel. The
     // link register generally holds the address the process wants to the
     // kernel to return to after it's done, so we'll install a software
     // breakpoint there.
     //
     // Calls into the kernel user page always follow the form:
     //  MVN ...
     //  <possible MOV lr,...>
     //  SUB PC, ...
     //
     //  So we look for this pattern and set a breakpoint on the LR at the SUB
     //  instruction.


     subsOp = ptrace(PTRACE_PEEKDATA, pid, pc, 0);
     if ((subsOp & 0xFFFF0FFF) == 0xe3e00a0f)
         foundMvn = true;

     if (foundMvn && ((subsOp & 0xFFF0F000) == 0xe240f000)) {
         foundMvn = false;
         lrOp = ptrace(PTRACE_PEEKDATA, pid, lr, 0);
         ptrace(PTRACE_POKEDATA, pid, lr, bkpt_inst);
         patch = true;
     }
     ptraceSingleStep();

     if (patch)
         ptrace(PTRACE_POKEDATA, pid, lr, lrOp);
 }


 TraceChild *
 genTraceChild()
 {
     return new ARMTraceChild;
 }
	/*
	* Copyright (c) 2010 ARM Limited
	* All rights reserved
	*
	* The license below extends only to copyright in the software and shall
	* not be construed as granting a license to any other intellectual
	* property including but not limited to intellectual property relating
	* to a hardware implementation of the functionality of the software
	* licensed hereunder. You may use the software subject to the license
	* terms below provided that you ensure that this notice is replicated
	* unmodified and in its entirety in all distributions of the software,
	* modified or unmodified, in source code or in binary form.
	*
	* Copyright (c) 2006-2009 The Regents of The University of Michigan
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are
	* met: redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer;
	* redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution;
	* neither the name of the copyright holders nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include <stdint.h>

	#include <cerrno>
	#include <cstdio>
	#include <cstring>
	#include <iostream>

	#include "arch/arm/tracechild.hh"

	using namespace std;

	ARMTraceChild::ARMTraceChild()
	{
	foundMvn = false;

	memset(&regs, 0, sizeof(regs));
	memset(&oldregs, 0, sizeof(regs));
	memset(&fpregs, 0, sizeof(vfp_regs));
	memset(&oldfpregs, 0, sizeof(vfp_regs));

	for (int x = 0; x < numregs; x++) {
	regDiffSinceUpdate[x] = false;
	}

	assert(sizeof(regs.uregs)/sizeof(regs.uregs[0]) > CPSR);
	}

	bool
	ARMTraceChild::sendState(int socket)
	{
	uint32_t regVal = 0;
	uint64_t message[numregs + 1];
	int pos = 1;
	message[0] = 0;
	for (int x = 0; x < numregs; x++) {
	if (regDiffSinceUpdate[x]) {
	message[0] = message[0] \| (1ULL << x);
	message[pos++] = getRegVal(x);
	}
	}

	size_t sent = 0;
	size_t toSend = pos * sizeof(message[0]);
	uint8_t messagePtr = (uint8_t )message;
	while (toSend != 0) {
	sent = write(socket, messagePtr, toSend);
	if (sent == -1) {
	cerr << "Write failed! " << strerror(errno) << endl;
	tracing = false;
	return false;
	}
	toSend -= sent;
	messagePtr += sent;
	}

	return true;
	}

	uint32_t
	ARMTraceChild::getRegs(user_regs &myregs, int num)
	{
	assert(num <= CPSR && num >= 0);
	return myregs.uregs[num];
	}

	uint64_t
	ARMTraceChild::getFpRegs(vfp_regs &my_fp_regs, int num)
	{
	assert(num >= F0 && num < numregs);
	if (num == FPSCR)
	return my_fp_regs.fpscr;

	num -= F0;
	return my_fp_regs.fpregs[num];
	}

	bool
	ARMTraceChild::update(int pid)
	{
	oldregs = regs;
	if (ptrace(PTRACE_GETREGS, pid, 0, &regs) != 0) {
	cerr << "update: " << strerror(errno) << endl;
	return false;
	}

	const uint32_t get_vfp_regs = 32;

	oldfpregs = fpregs;
	if (ptrace((__ptrace_request)get_vfp_regs, pid, 0, &fpregs) != 0) {
	cerr << "update: " << strerror(errno) << endl;
	return false;
	}

	for (unsigned int x = 0; x < numregs; x++)
	regDiffSinceUpdate[x] = (getRegVal(x) != getOldRegVal(x));

	return true;
	}

	int64_t
	ARMTraceChild::getRegVal(int num)
	{
	if (num <= CPSR)
	return getRegs(regs, num);
	else
	return (int64_t)getFpRegs(fpregs, num);
	}

	int64_t
	ARMTraceChild::getOldRegVal(int num)
	{
	if (num <= CPSR)
	return getRegs(oldregs, num);
	else
	return (int64_t)getFpRegs(oldfpregs, num);
	}

	ostream &
	ARMTraceChild::outputStartState(ostream & os)
	{
	uint32_t sp = getSP();
	uint32_t pc = getPC();
	uint32_t highestInfo = 0;
	char obuf[1024];
	sprintf(obuf, "Initial stack pointer = 0x%08x\n", sp);
	os << obuf;
	sprintf(obuf, "Initial program counter = 0x%08x\n", pc);
	os << obuf;

	//Output the argument count
	int32_t cargc = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
	sprintf(obuf, "0x%08x: Argc = 0x%08x\n", sp, cargc);
	os << obuf;
	sp += 4;

	//Output argv pointers
	int argCount = 0;
	int32_t cargv;
	do {
	cargv = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
	sprintf(obuf, "0x%08x: argv[%d] = 0x%08x\n",
	sp, argCount++, cargv);
	if (cargv)
	if (highestInfo < cargv)
	highestInfo = cargv;
	os << obuf;
	sp += 4;
	} while (cargv);

	//Output the envp pointers
	int envCount = 0;
	uint32_t cenvp;
	do {
	cenvp = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
	sprintf(obuf, "0x%08x: envp[%d] = 0x%08x\n",
	sp, envCount++, cenvp);
	os << obuf;
	sp += 4;
	} while (cenvp);
	uint32_t auxType, auxVal;
	do {
	auxType = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
	sp += 4;
	auxVal = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
	sp += 4;
	sprintf(obuf, "0x%08x: Auxiliary vector = {0x%08x, 0x%08x}\n",
	sp - 8, auxType, auxVal);
	os << obuf;
	} while (auxType != 0 \|\| auxVal != 0);
	//Print out the argument strings, environment strings, and file name.
	string current;
	uint32_t buf;
	uint32_t currentStart = sp;
	bool clearedInitialPadding = false;
	do {
	buf = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
	char * cbuf = (char *)&buf;
	for (int x = 0; x < sizeof(uint32_t); x++) {
	if (cbuf[x])
	current += cbuf[x];
	else {
	sprintf(obuf, "0x%08x: \"%s\"\n",
	currentStart, current.c_str());
	os << obuf;
	current = "";
	currentStart = sp + x + 1;
	}
	}
	sp += 4;
	clearedInitialPadding = clearedInitialPadding \|\| buf != 0;
	} while (!clearedInitialPadding \|\| buf != 0 \|\| sp <= highestInfo);
	return os;
	}

	bool
	ARMTraceChild::step()
	{
	const uint32_t bkpt_inst = 0xe7f001f0;

	uint32_t lr = getRegVal(14);
	uint32_t pc = getPC();
	uint32_t lrOp, subsOp;
	char obuf[128];
	bool patch = false;

	// Since ARM uses software breakpoints behind the scenes, they don't work
	// in read only areas like the page of routines provided by the kernel. The
	// link register generally holds the address the process wants to the
	// kernel to return to after it's done, so we'll install a software
	// breakpoint there.
	//
	// Calls into the kernel user page always follow the form:
	// MVN ...
	// <possible MOV lr,...>
	// SUB PC, ...
	//
	// So we look for this pattern and set a breakpoint on the LR at the SUB
	// instruction.


	subsOp = ptrace(PTRACE_PEEKDATA, pid, pc, 0);
	if ((subsOp & 0xFFFF0FFF) == 0xe3e00a0f)
	foundMvn = true;

	if (foundMvn && ((subsOp & 0xFFF0F000) == 0xe240f000)) {
	foundMvn = false;
	lrOp = ptrace(PTRACE_PEEKDATA, pid, lr, 0);
	ptrace(PTRACE_POKEDATA, pid, lr, bkpt_inst);
	patch = true;
	}
	ptraceSingleStep();

	if (patch)
	ptrace(PTRACE_POKEDATA, pid, lr, lrOp);
	}


	TraceChild *
	genTraceChild()
	{
	return new ARMTraceChild;
	}